Trees, Shrubs, Vines and Plants. 371 



The following spring, feeding is resumed in the larger branches, 

 and by the end of this season the borers are full grown. E^rly the 

 next spring, they work out to the surface and change to quiet 

 pupae, from which the adult moths emerge during the summer. 



Spraying for these insects is useless, as the moths do not feed 

 and the borers work inside the branches almost entirely. Infested 

 limbs are quite easily recognized by the woody, partly digested 

 material thrown out of the openings of the tunnels, and these 

 limbs can be cut off and burned, or if not too badly injured a 

 little carbon disulphide (obtained from druggists) can be injected 

 into the openings of the tunnels, which should then be immediately 

 closed with putty or soap, so that the gas produced may not es- 

 cape, but follow along the tunnel and kill the borer. Badly in- 

 fested trees are usually too difficult to treat and should be de- 

 stroyed. Careful watching during the summer, to discover parts 

 attacked before it is too late, followed by the removal or treat- 

 ment of the infested branches, as described, is the best treatment 

 at present known. 



The San Jose Scale. 



The San Jos6 Scale is probably a native of China, but is now 

 present nearly everywhere in the United States. It feeds upon a 

 large number of trees and shrubs, seriously checking their growth, 

 and in many cases destroying them entirely. Besides fruit trees 

 and currants, on which it is a most serious pest, it is often very 

 abundant and injurious to the following shade trees and shrubs: 

 Amelanchier, Comus, Crataegus, Cydonia japonica, Populus, 

 Prunus, Ptelea, Pyrus, Ribes, Rosa, Salix, Sorbus, Syringa, Tilia, 

 Toxylon and Ulmus, of different species (see tabulated list of 

 plants, page 142). It is also often found on other trees and 

 shrubs, but the above are those most liable to be much injured. 



The adult insect is smaller than a pin-head and covered by a 

 hard shell or scale, circular in outline, and brown or grayish in 

 color. It is usually most abundant on the smaller branches and 

 twigs, but when very abundant may also be present on the leaves. 

 When winter sets in all ages may be present, but the very young 

 and the adult scales die during the winter, leaving only those from 



